Ko thấy gì hết

Đó! Mình vẽ xấu vs lại số văng tứ tung, nhưng cũng dễ nhìn đúng hông? Bạn làm đi.

\(=\left(\dfrac{1}{2}+\dfrac{4}{5}-\dfrac{4}{3}\right)\left(2.3+4.28-1.28\right)\)

\(=\dfrac{15+24-40}{30}\cdot\left(2.3+3\right)\)

\(=\dfrac{-1}{30}\cdot\dfrac{53}{10}=\dfrac{-53}{300}\)

Pt: SO2 + 2NaOH ---> Na2SO3 + H2O

nSO2= 1,28/64=0,02 mol

thấy nSO2= nNa2SO3 = 0,02 mol

=> m muối = 0,02*<32+16*3+22*2>=2,52 g

\(=\frac{19}{4}+\left(-\frac{37}{100}\right)+\left(-\frac{32}{25}\right)+\left(-\frac{5}{2}\right)+\frac{7}{2}\)

\(=\frac{219}{50}+\left(-\frac{32}{25}\right)+\left(-\frac{5}{2}\right)+\frac{7}{2}\)

\(=\frac{31}{10}+\left(-\frac{5}{2}\right)+\frac{7}{2}\)

\(=\frac{31}{10}+\left(-\frac{25}{10}\right)+\frac{35}{10}\)

\(=\frac{41}{10}\)

       \(4\frac{3}{4}+\left(-0,37\right)+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{2}\)

\(=\frac{19}{4}-\frac{37}{100}-\frac{128}{100}-\frac{25}{10}+\frac{7}{2}\)

\(=\frac{475}{100}-\frac{37}{100}-\frac{128}{100}-\frac{250}{100}+\frac{350}{100}\)

\(=\frac{410}{100}=4,1\)

\(12.8\cdot35+1.28\cdot650=12.8\cdot35+12.8\cdot65\\ =12.8\cdot\left(35+65\right)=12.8\cdot100=1280\)